The plant growth-promoting rhizobacterium Pseudomonas aeruginosa 7NSK2 produces three siderophores when iron is limited: the yellow-green fluorescent pyoverdin, the salicylate derivative pyochelin, and salicylic acid. This Pseudomonas strain was shown to be an efficient antagonist of Pythium-induced damping-off. The role of pyoverdin and pyochelin in the suppression of Pythium splendens was inv...

Siderophores are low molecular weight secondary metabolites produced by microorganisms under iron stress as a specific chelator. In the present study, rhizospheric bacterium was isolated from rhizosphere of sesame plants Salem district, Tamil Nadu, India and later identified Bacillus subtilis LSBS2. It exhibited multiple plant-growth-promoting (PGP) traits such hydrogen cyanide (HCN), ammonia, ...

The main siderophores produced by streptomycetes are desferrioxamines. Here we show that Streptomyces sp. ATCC 700974 and several Streptomyces griseus strains, in addition, synthesize a hitherto unknown siderophore with a catechol-peptide structure, named griseobactin. The production is repressed by iron. We sequenced a 26-kb DNA region comprising a siderophore biosynthetic gene cluster encodin...

One alternative method for drug delivery involves the use of siderophore-antibiotic conjugates. These compounds represent a specific means by which potent antimicrobial agents, covalently linked to iron-chelating siderophores, can be actively transported across the outer membrane of gram-negative bacteria. These "Trojan Horse" antibiotics may prove useful as an efficient means to combat multi-d...

Iron transport represents a unique problem in biology. In general, organisms have large requirements for iron, creating a need for both transport and storage systems. For aerobic organisms this means that femc ion, which is completely insoluble as the hydroxide at neutral pH, must be complexed so that it can be solubilized for both mobilization and storage. For bacteria this problem is particul...

While predators and parasites are known for their effects on bacterial population biology, their impact on the dynamics of bacterial social evolution remains largely unclear. Siderophores are iron-chelating molecules that are key to the survival of certain bacterial species in iron-limited environments, but their production can be subject to cheating by non-producing genotypes. In a selection e...

Under field conditions, inoculated rhizobial strains are at a survival disadvantage as compared to indigenous strains. In order to out-compete native rhizobia it is not only important to develop strong nodulation efficiency but also increase their competence in the soil and rhizosphere. Competitive survival of the inoculated strain may be improved by employing strain selection and by genetic en...

Microbial drug resistance is partly due to hindered diffusion through the membrane of microbial cells and active transport mechanisms. An approach to counter such resistance uses the bacterial iron transport system. Extracellular free iron is scarce in vertebrates, yet essential for microbial growth (Anderson et al., 2012). A mechanism displayed by microbial pathogens to cope with iron scarcity...

Siderophores are compounds secreted under low iron stress, that act as a specific ferric iron chelate agents and due to their potentialities in the biological control of phytopathogenic fungi and bacteria, their study has been stimulated in recent years. Siderophores produced by different Pseudomonas species have been widely studied as biological agents and it is an alternative to take into acc...

Ferric enterobactin utilization by Bordetella bronchiseptica and Bordetella pertussis requires the BfeA outer membrane receptor. Under iron-depleted growth conditions, transcription of bfeA is activated by the BfeR regulator by a mechanism requiring the siderophore enterobactin. In this study, enterobactin-inducible bfeA transcription was shown to be TonB independent. To determine whether other...